| Pékin, Chine | 10/02 04:30 | 25 | [58] Matteo Berrettini v Mayer, Leonardo [52] | 6-3,6-2 | |
| US Open, New York, USA | 08/28 15:00 | 23 | [89] Laslo Djere v Mayer, Leonardo [43] | Retired | |
| Winston-Salem, USA | 08/21 23:10 | 25 | [41] Mayer, Leonardo v Kyle Edmund [16] | 3-6,3-6 | |
| Winston-Salem, USA | 08/20 19:00 | 24 | [41] Mayer, Leonardo v Sugita, Yuichi [93] | 6-3,7-6 | |
| Cincinnati, USA | 08/17 18:00 | 26 | [50] Mayer, Leonardo v Federer, Roger [2] | 1-6,6-7 | |
| Cincinnati, USA | 08/14 18:35 | 25 | [17] Lucas Pouille v Mayer, Leonardo [50] | 6-7,4-6 | |
| Cincinnati, USA | 08/13 18:30 | 24 | [133] Michael Mmoh v Mayer, Leonardo [50] | 4-6,6-1,4-6 | |
| Hamburg, Germany | 07/29 13:00 | 29 | [81] Nikoloz Basilashvili v Mayer, Leonardo [36] | 6-4,0-6,7-5 | |
| Hamburg, Germany | 07/28 10:00 | 28 | [113] Jozef Kovalik v Mayer, Leonardo [36] | 7-6,4-6,6-7 | |
| Hamburg, Germany | 07/27 11:30 | 27 | [36] Mayer, Leonardo v Diego Schwartzman [12] | 6-3,4-6,6-3 | |
| Hamburg, Germany | 07/25 15:30 | 26 | [37] Gaël Monfils v Mayer, Leonardo [36] | 1-6,5-7 | |
| Hamburg, Germany | 07/23 09:00 | 25 | [36] Mayer, Leonardo v Albert Ramos-Vinolas [40] | 6-3,6-2 | |
| ATP Bastad | 07/16 11:25 | 25 | [75] Matteo Berrettini v Mayer, Leonardo [36] | 3-6,6-3,6-4 | |
| Wimbledon, London, Great Britain | 07/02 10:30 | 23 | [64] Jan-Lennard Struff v Mayer, Leonardo [36] | 3-6,6-7,7-6,7-6,6-1 | |
| Eastbourne, Great Britain | 06/27 14:35 | 26 | [62] John Millman v Mayer, Leonardo [36] | 7-6,7-6 | |
| Eastbourne, Great Britain | 06/26 10:00 | 25 | [53] Simon, Gilles v Mayer, Leonardo [36] | 4-6,6-7 | |
| London, Great Britain | 06/20 11:00 | 26 | [62] Frances Tiafoe v Mayer, Leonardo [38] | 6-4,2-6,6-4 | |
| London, Great Britain | 06/19 11:30 | 25 | [38] Mayer, Leonardo v Anderson, Kevin [8] | 7-6,4-6,7-6 | |
| Open de France | 05/29 17:25 | 23 | [42] Mayer, Leonardo v Benneteau, Julien [62] | 6-2,6-7,2-6,3-6 | |
| ATP - Rome | 05/14 10:55 | 24 | [42] Mayer, Leonardo v David Goffin [10] | 1-6,2-6 | |
| ATP - Madrid | 05/10 16:10 | 26 | [45] Mayer, Leonardo v Alexander Zverev [3] | 4-6,2-6 | |
| ATP - Madrid | 05/09 15:30 | 25 | [45] Mayer, Leonardo v Verdasco, Fernando [37] | 6-2,6-1 | |
| ATP - Madrid | 05/08 10:00 | 24 | [19] Fabio Fognini v Mayer, Leonardo [45] | 3-6,4-6 | |
| ATP - Estoril | 05/01 16:15 | 25 | [45] Mayer, Leonardo v Nicolas Jarry [65] | 6-3,6-7,4-6 | |
| ATP - Barcelone | 04/25 16:05 | 25 | [45] Mayer, Leonardo v Karen Khachanov [37] | 4-6,3-6 | |
| ATP - Barcelone | 04/23 16:20 | 24 | [45] Mayer, Leonardo v Zverev, Mischa [52] | 6-3,6-0 | |
| ATP - Miami | 03/24 15:00 | 24 | [36] Borna Coric v Mayer, Leonardo [45] | 6-7,6-3,6-4 | |
| ATP - Miami | 03/22 16:25 | 23 | [45] Mayer, Leonardo v Young, Donald [110] | 3-6,6-4,6-2 | |
| ATP - Indian Wells | 03/15 00:50 | 26 | DEL POTRO J.M. v Mayer, Leonardo | 3-6,7-6,6-3 | |
| ATP - Indian Wells | 03/13 19:40 | 25 | Mayer, Leonardo v Taro Daniel | 6-4,6-1 |